Feature request: postgresql_comment resource

[strawberrymetropolis]

Thank you, all contributors, for this very useful Terraform provider! We use it to set up databases, schemas, roles, and role grants - all of which need proper documentation. This is why we'd love to see another resource being supported:

• Resource: postgresql_comment
• Specification: https://www.postgresql.org/docs/current/sql-comment.html
• In order to get started lightweighted, it might be advisable to only support the most common database objects initially: ROLE, DATABASE, SCHEMA, TABLE, COLUMN

[glauberferreiranees]

#450